This feature is called Stock Sync Credit.
The minimum credit will be 100 per transaction and the maximum is 10,000 SKU.
The total amount of SKU is not limited.
To use the Add product function, You need to go to Setup New Feed > I want to add new products.
The user can keep on adding the number of SKUs to be added as a prepaid plan.
The Stock Sync Credit is available for all users.
Access to Full Feature users can purchase Stock Sync credit and perform any Adding or Remove product. This is also applicable to FREE users as well.
Scroll down to the Credit section to purchase more.